From 01a98d03ccf1e09050c37e6129294e353a1c0dce Mon Sep 17 00:00:00 2001
From: Jonathan Schultz <nccu-schultz-lab@users.noreply.github.com>
Date: Sat, 26 Sep 2026 19:04:58 +0000
Subject: [PATCH] fix(tests): build test wheels from a private source copy

tests/test_packaging.py ran `python -m build` in the repo root from every
test. setuptools stages builds in build/ and *.egg-info inside the source
tree, so under pytest-xdist parallel builds deleted each other's staging
directory mid-build:

    error: [Errno 2] No such file or directory: 'build/bdist.linux-x86_64/wheel'

_build_wheel now copies the checkout (minus .git, build/dist droppings,
caches, *.sif and the local .plans symlink) into the test's tmp_path and
builds there. tests/ is kept in the copy so the "tests are not shipped"
check still has something to exclude.

Reproduced first: 4/4 runs of `pytest -n 5 tests/test_packaging.py` had a
failure. After the fix: 0/4, and the file passes serially.

Contributions:
- Claude (Opus 5.5): code edits, review, and conceptual discussion
- Jonathan Schultz: overall vision, planning, review, and orchestration

Co-authored-by: Jonathan Schultz <nccu-schultz-lab@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
---
 tests/test_packaging.py | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/tests/test_packaging.py b/tests/test_packaging.py
index 706e926..7e12c30 100644
--- a/tests/test_packaging.py
+++ b/tests/test_packaging.py
@@ -18,6 +18,7 @@
 
 from __future__ import annotations
 
+import shutil
 import subprocess
 import sys
 import zipfile
@@ -28,11 +29,38 @@
 REPO_ROOT = Path(__file__).parent.parent
 
 
+# Build droppings and VCS data that a private source copy must not carry
+# over: a stale build/ or *.egg-info could leak old files into the wheel.
+_COPY_IGNORE = shutil.ignore_patterns(
+    ".git",
+    "build",
+    "dist",
+    "*.egg-info",
+    "__pycache__",
+    ".pytest_cache",
+    ".mypy_cache",
+    ".ruff_cache",
+    "*.sif",
+    ".plans",  # local symlink to the planning repo (CLAUDE.md)
+)
+
+
 def _build_wheel(tmp_path: Path) -> Path:
-    """Build the project wheel into ``tmp_path`` and return its path."""
+    """Build the project wheel into ``tmp_path`` and return its path.
+
+    setuptools stages every build in ``build/`` and ``*.egg-info`` inside the
+    source tree, so parallel builds from the same checkout (pytest-xdist runs
+    these tests on several workers) delete each other's staging directory
+    mid-build ("No such file or directory: 'build/bdist.<plat>/wheel'").
+    Building from a private copy of the tree gives each test its own. The
+    copy keeps ``tests/``, so the "tests are not shipped" check still has
+    something to exclude.
+    """
+    src = tmp_path / "src"
+    shutil.copytree(REPO_ROOT, src, ignore=_COPY_IGNORE, symlinks=True)
     subprocess.run(
         [sys.executable, "-m", "build", "--wheel", "--outdir", str(tmp_path)],
-        cwd=REPO_ROOT,
+        cwd=src,
         check=True,
         capture_output=True,
         text=True,